Cutting of trees can be done for many reasons. In some aspects the tree cut can be large enough to be a useful source for lumber or other commercial uses. In many other cases, trees of much smaller diameter are cut simply as a matter clearing of land, brush and the like. One of the common ways of cutting relatively smaller trees is to use a manually carried power saw, known as a clearing saw. The clearing saw typically has a gasoline engine so that it may be used in remote areas where electric power would not be available. The engine is mounted at one end of a relatively long handle. A drive shaft couples the engine to a rotary saw blade located at the other end of the handle. A yoke-like mechanism may be used to position and carry the clearing saw. Such a rotary saw blade may have a diameter of in the order of 12 inches. Such a device can be used for cutting trees to approximately six inches in diameter.
Another device used for cutting trees of large diameter involves the standard chain saw. The chain saw has a gasoline powered motor which drives a chain. The chain is guided around its cutting length by some type of bar. The teeth to cut the wood are affixed to the chain and move along the cutting bar with the chain. Depending upon the length of the support bar and chain, chain saws can cut trees of very substantial diameter.
Whatever the method of cutting the tree, once the tree has been cut, it is usually desirable to ensure that the plant does not regenerate growth through the stump. In many locations it is far better to reforest with particular species of trees rather than encourage the stump to grow again. A healthy tree cut from a stump with an established root system will typically regenerate itself. However, the regenerated tree may not be desirable in terms of size, species or other characteristics such as the number of branches which may result from the cut stump. Thus, in many cases, it is desirable to ensure that the stump is killed so that the plant will not attempt to regenerate itself from the cut stump. Typically, this has been done by applying a suitable herbicide to the freshly cut stump. It is particularly effective to apply herbicide shortly after the tree is cut before the sap flowing in the stump seals off the open pores in the sap wood.
In many cases where land is being cleared and trees cut down, a first individual manipulates whatever type of tree felling instrument is being used to cut the trees. Then, steps are taken to apply herbicide to the stump. This may involve the person who felled the tree who may be obliged to put down the saw and then apply a herbicide. Alternatively, a second person will follow the tree feller or fellers and treat the newly created stumps. Heretofore, one of the most convenient ways of treating the felled stump has been to use a pressure sprayer. A pressure sprayer may involve a tank or reservoir with a flexible hose. The flexible hose or conduit may be attached to a wand-like device which can be carried in the hand. At the terminal end of the wand a spray head or nozzle is provided so that fluid may be delivered from the reservoir to the spray head. To facilitate this, the sprayer may be pressurized by means of a hand operated air pump. The person applying herbicide to the freshly cut stumps then walks through the areas of new stumps and sprays the herbicide on the fresh cut stump.
While this is effective in killing the stump, several problems have been noted. The spray pattern may not be as accurate as desired. Particularly on days when there is any wind present while the fresh cut stumps are being sprayed, there is a significant danger that the spray will be applied not only to the stump as desired, but also to adjacent vegetation. Because the herbicide is most effective when applied to the sapwood which is located around the periphery of the plant, the spray is routinely applied not only to the desired sapwood area, but also immediately adjacent the stump on the ground. This carries with it the possibility that the herbicide will be applied to desirable vegetation which may surround the freshly cut stump. Because the pressure in the reservoir may change as the liquid herbicide is applied to the stump, the spray pattern may also change and thus the accuracy with which the herbicide is applied may change depending upon the pressure in the spray apparatus.
Another approach has been taken to address the problem of applying the herbicide to a freshly cut stump. A device comprising a combination brush cutter and stump treater has been proposed. Such a device is available from Enso. The Enso device is intended for addition to clearing saws of the type referred to above having a rotating cutting blade in the order of approximately 12 inches in diameter. The stump treating apparatus includes a reservoir which is supported on the body of the operator. There is a conduit which passes along the length of the shaft of the clearing saw which terminates in a spray nozzle. A feed pump may be provided to facilitate movement of the herbicide from the tank to the nozzle. The spray nozzle is arranged adjacent to the cutting blade with the intent that a coating of herbicide is sprayed onto the cutting blade while the cutting blade is in operation. This device thus provides a one step process. As the blade spins to cut the wood it is coated with the herbicide thereby applying herbicide as the plant is cut.
One of the problems that remains with this device is that there is again a spray discharge of the herbicide. In addition, by spraying the herbicide on the blade which is rotating at relatively high speed, there is also the possibility that the liquid discharged onto the blade will be thrown centrifugally from the blade and thus applied to other plants in the locus of the tree being cut. Thus, this device is also subject to problems when there is wind present and may apply herbicide to plants other than the tree being cut.
Accordingly, there is a need for a simple effective way to apply herbicide to a freshly cut stump, while minimizing the chances of application of herbicide to plants other than the freshly cut stump.